1. Field
The present disclosure generally relates to multi-chip modules (MCMs) and techniques for fabricating MCMs. More specifically, the present disclosure relates to an MCM that includes a multi-level interposer plate between a base plate and an array of chips in the MCM.
2. Related Art
Multi-chip modules (MCMs) that facilitate proximity communication between multiple integrated circuits (ICs) or chips (such as capacitively coupled proximity communication) are being developed for next generation high-performance computers. In these MCMs, chips are often positioned face-to-face so that information can be communicated between proximity connectors (such as metal pads) on the surfaces of the facing chips.
In order to enable ultrafast chip-to-chip communication speeds via capacitive coupling between the metal pads on the facing chips, these chips need to be aligned with each other. In addition, to address the so-called ‘known-good-die’ problem, and thus to facilitate scaling to large numbers of chips, the chips are ideally fully tested after assembly because it is expensive to replace the ceramic substrate in an MCM in the event of a bad or faulty chip. Consequently, there is increasing need to provide remateable interconnects between the chips and the ceramic substrate in such MCMs.
Wire bonding and solder-ball flip-chip bonding are widely used in electronic packages to produce chip-to-substrate interconnects. However, these packaging technologies usually do not facilitate remateable interconnects in a large array of chips.
Stressed-metal spring or claw interconnects (which are henceforth referred to as ‘micro-spring connectors’) are promising candidates for use in remateable chip-to-package interconnects. In particular, micro-spring connectors offer low-resistance electrical contacts even after multiple engage-disengage cycles. However, it can be difficult to fabricate an MCM having a large, multi-level array of chips that are coupled using micro-spring connectors while maintaining the precise geometric alignment that is needed for proximity communication. As a consequence, the costs of such MCMs can be prohibitive.
Hence, what is needed is an MCM and an associated fabrication technique which do not suffer from the above-described problems.